The invention relates to a brake system as defined hereinafter.
This kind of brake system, in which the brake boosting occurs only or additionally outside the actual master brake cylinder, is described in U.S. Pat. No. 4,678,243, for instance. In that patent, by means of an additional plunger included in a brake circuit, an additional brake pressure can be exerted upon wheel brake cylinders. The pressure buildup in the additional plunger is effected independently of a brake pressure that acts upon a brake pedal. The control is effected via a travel sensor, associated with a piston in the brake booster, and via a pressure sensor associated with the additional plunger. Thus this additional plunger has the sole task of raising the brake pressure in the brake circuit independently of the brake pressure acting on the brake pedal.